https://www.cisco.com/c/en/us/support/docs/field-notices/740/fn74099.html
Field Notice: FN74099 - IW9165: Catalyst IW9165 Access Points May Not Failover to PoE When Dual...
When DC power is lost, Cisco Catalyst IW9165 Access Points fail to properly boot after switching to Power over Ethernet (PoE) power.